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UNITE S'IA'IES EIENT FFIQE.

THOMAS MCLAUGHLIN, 0F NEW YORK, N. Y.

EXPANSION-GEAR FOR PUPPET-VALVES.

Specification of Letters Patent No. 7,056, dated January 29, 1850.

To all whom it may concern Be it known that I, THOMA; MCLAUGH- LIN, ofthe city, county, and State of New York, have invented a new andImproved Cut-Off for Steam-Engines; and I do hereby declare that thefollowing is a full and eXact description of the same.

The nature of my invention consists in the producing of a more easy andsafe cutoff1 for steam, by the combination and attachment to the end ofthe rock shaft, of an arm or lever having an angular quadrant shapedopening in it of about 90 degrees (more or less), and attached to theback of it, by means ofv a pin or bolt, through its lower end, aquadrant shaped plate, which has three holes pierced through it, (agreater or lesser number may be used if required) for the purpose ofproportioning the half, three quarter, or full supply of steam. Intoeither of these holes, and through the angular opening in the arm, isattached one end of a connecting rod, the other being bolted to areciprocating plate connecting the ends of the two eccentric rods on themain shaft. But to describe my invention more particularly I will referto the accompanying drawings, the same letters of reference in theseveral drawings referring to the same parts wherever they occur.

Figure l, a perspective view; Fig. 2, a rock shaft arm or lever; Fig. 3,a back or quadrant shaped plate of the rock shaft arms; Fig. 4,reciprocating plate and connecting rod; Fig. 5, a side elevation.

Letter A, flooring. B, frame, for supporting the main shaft. C, mainshaft. D, crank on the end of it. E', E2, two eccentrics on the mainshaft. These eccentrics are keyed on the main shaft so as to make adifference of lead or drawing of the rods of about an eighth of theircircumference, (that is, of the eccentrics) and are so relativelyplaced, for the purpose of obtaining the necessary motion to graduatethe cutting off of the steam at the time required. F, F2, two eccentricrods. G, support for holding up the ends of the eccentric rods, attachedto a brace or side of the engine room. H, reciprocating plate, attachedby bolts, through its upper and lower left hand corners, to the ends ofthe two eccentric rods, for the purpose of reciprocating the oppositemotions of the two eccentrics. In the back of this plate are three holesa, o, c, (a greater or lesser number may be used if required) into whichis attached by a bolt one end of the4 connecting rod I. the other endbeing secured at a crresponding hole (by a bolt z') in the quadrantshaped plate J at the back of the lever or arm K, and through theangular opening of which, the bolt passes. This plate J is secured atits lower ends by a center pin (J 2) to the lower end of the arm K, forthe purpose of vibrating or allowing play to the motion of theeccentrics, while the steam is shut off, and the piston completing itsstroke. By this time the eccentrics have carried the bolt or pin acrossthe angular opening in the arm K, and is ready to act upon the innerside of the opening, for opening the valve again for another stroke. Inthe middle of the plate J are three holes corresponding with the holesin the back of the reciprocating plate. When the connecting rod I isattached to the reciprocating and quadrant plates at the points a, a,the steam would then be on throuhout the entire stroke; if attached atb, Z), it would be cut off at half stroke, and if at c, c, at quarterstroke. This arrangement of attaching the connecting rod to thereciprocating plate and quadrant plate respectively, by pins or bolts,may be varied so as to use adjusting screws into rods on which theconnecting rod may be raised 0r lowered without the necessity ofdisconnecting it from the reciprocating and quadrant plates and which inpractical operations, is intended as a part of the invention. L, rockshaft. M, frame supporting rock shaft. N, brace for steadying rock shaftframe. O, O, toes on rock shaft. P, P, lifters on valve rods R, R.

The operation of these several parts are that when the two eccentricsare keyed on the main shaft so as to make a difference in their lead ordrawing of about one eighth of their circumference, and the crank is onits lower center, the valves are down, and if the connecting rod I benow attached to the reciprocating plate and quadrant plate,respectively, at the holes o, 7), and the engine started in thedirection of the arrow, the steam will be cut off at half stroke; thatis, the eccentric E throws forward the lower end of the reciprocatingplate, while for a time the eccentric E2 lifts and holds the upper endof it nearly perpendicular so as to allow the eccentric E to cause theprojecting forward of the connecting rod, and pressing of the pin z',against the inner side is bein performed the pin (2') plays or passes trough the open space in the arm till it comes in contact with theopposite side of the opening, when itY opens the valve again for thenext stroke. In changing the point of attachment to a', a, or c, c, orother points when used the same operation is performed, the only changerequired to vary the cut 0H being in the attaching of the connectingrod.

Having now described my invention I will state what I claim Vand desireto secure by Letters Patent.

What I claim therefore is- The use and employment of the connecting rodI7 acted upon by two eccentrics, in combination with the reciprocatingplate H, and arm K having an angular opening in it, and quadrant shapedplate J or its mechanical equivalent attached thereto, for the purposeof working puppet valves, in form and manner substantially as herein setforth.

THOMAS MCLAUGHLIN.

Witnesses:

CHARLES L. BARRifi'r, JOHN ADAMS.`

